6.4
Welding In a Valve with Pipe Connection
6.4.1
Valve with Welded Ends
This section describes the welding procedure for the valve housing.
Warning!
Spring tension in the valve
Danger of injury when opening the clamp connections on the actuator or on
the housing as the released spring pretension will suddenly lift the actuator.
► Therefore, release the spring tension before detaching the clamp
connections by pressurizing the actuator with compressed air at max. 8 bar.
Notice
Seals are wearing parts
Old seals will cause malfunction of the valve
► When fitting the valve be sure to fit new housing O-rings.
Notice
Welding distortions
An open housing can warp during welding.
► To avoid welding distortions, always seal the housing before welding.
Carry out the following steps:
1.
Release the spring tension.
2.
Remove the valve insert, see chapter Section 9.5, Page 30.
3.
Weld the housing, without sealing rings, into position, ensuring that the
connection is free of stress.
4.
Fit the housing into place and tack it.
5.
To avoid welding distortions, always seal the housing before welding.
6.
Flush the housing with forming gas from the inside to push the oxygen out of
the system.
7.
Weld the housing into the pipe system; use welding filler if necessary. When
technically possible, use the WIG-Orbital welding process with pulse
configuration, according to guidelines EHEDG documentation. 35.
8.
Passivate the seam after welding.
9.
Assemble the valve and depressurize the actuator..
10.
Fit the seals.
®
The valve disk is lowered.
®
Install the valve with welded ends.
Assembly and installation
Welding In a Valve with Pipe Connection
430BAL008565EN_1
21.03.2022
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